Improvement in bridge-girders



UNITED STATES DAVID HAMMOND AND W. R. REEVES, OF CANTON, OHIO.

yIMPROVEMENT `IN BRIDGE-GIPLDEPLS.

Specification forming part of Letters Patent N0, 43,202. dated June 21, 1864.

To all whom it may concern Beit known that we, DAVID HAMMOND and XV. R. REEVES, both of Canton, in the county of Stark and State of Ohio, have invented a new and useful Improvement in Vrought-Iron Trussed Girders for Bridges and Other Structures and We do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the saine, reference being had t3 the accompanying drawings, forminga part of this specification, in which- Figure 1 is a side view otl a bridge. Fig. 2 is a plan ot' the same.' Fig. 3 is a transverse vertical section of the same. Figs. 4 and 5 are transverse sections of one ofthe two girders of which the bridge is composed.

Similar letters ot' reference indicate like parts.

This invention consists in a noval construction of a wrought-iron arch and novel combination of an arch and string-piece, suspenY sion-rods, and diagonal braces, whereby we obtain a'girder ot' great strength and stitt'ness with a comparatively small Weight.

The arch A of each girder is composed ot' three continuous pieces, a a b, of dat bariron, ot' which two, c a, are set up edgewise opposite each other and ata distance apart equal to the thickness of the suspension-rods B B and diagonal braces O O, and the third,

Y b, is laid down over the upper edges of c c and secured thereto at suitable distances by wrought or cast iron` clampingpieccs c c, screwbolts d d, and nuts e c.

The clamping-pieces consist of plates of iron notched or grooved in their upper sides, as shown in Fig. 5, to receive and tit the lower edges 'oi' the bars a a, under which` they are placed. The bolts d d, having their heads downward, pass through holes in the said clamping-plates and holes in the top piece, i), of the arch, as shown in Fig. 4, and are secured by the nuts c e being screwed onto them above the top piece, b. The stringpiece D is also composed of a continuous straight piece of iiat baniron set up edgewise and arranged to form a chord to the arch A, to the ends of which it is secured by being placed between the pieces a c and having bolts or rivets h inserted through the whole. The said stringpiece and arch are also connected together at suitable distances by the suspension-rods B and diagonal braces O, which are placed between the pieces a c ot the arch. The rods and braces are made ot' Hat bar-iron, and their upper ends are iinished off in the form ot' screw-pins which pass through holes in the piece b, and are secured by nuts ff above the arch. The upper parts of the said rods and braces a-re further secured to the arch by screw-bolts or rivets g g, inserted through them and through the pieces ca. The lower parts of the said rods and braces are made of hook form, as shown iu Fig. 3, the hook-formed portions receiving within them and supporting the stringpiece, and being clamped thereon by screw--bolts or .rivets 't' il, inserted through them and the string-piece. The arch-girder thus constructed has its ends fitted and supported in cast-iron shoes E E, so formed as to support the arch against any tendency to longitudinal extension. These shoes are secured to the arch and string-piece by making the bolts li h pass through them as well as through the arch and string-piece. The stringv piece, being rmly secured to the ends of Vthe arch, acts as a tensionbrace to prevent the elongation ot' the arch. The two or more of these girders ot' which a bridge is composed are braced transversely in any suitably manner. The roadway is supported upon transverse timbers F F, placed across and resting on the' DAVID HAMMOND. W. B. REEVES.

Viinesses:

W. W. CLARK, HARMAN S'rIDGEa. 

